Biology subjects

Poole, J.

Publications and source records attributed to Poole, J..

5 recordsLinked to original sources

bioRxiv2026

Development of a Matrix-Matched Calibration Curve for Multi-Site Quantification of Neu5Gc-Bearing N-Glycans

N-glycolylneuraminic acid (Neu5Gc) has been repeatedly associated with human cancer, but reliable detection has remained elusive, generating controversy regarding its presence in human samples. To address this, matrix-matched calibration curves, which have been pioneered in proteomics and metabolomics for assessing changes in complex mixtures, were measured of released N-glycans at four orders of magnitude dynamic range in defined mixtures, systematically benchmarking Neu5Gc-containing N-glycan detection across multiple LC-MS platforms and sites. Orthogonally, the gold-standard analytical method, consisting of fluorescence detection of labelled monosaccharides separated by LC, was applied to the same samples, yielding absolute concentrations of Neu5Gc. LC-MS demonstrated an extended detection range of three or more orders of magnitude while retaining intact N-glycan measurement, improving assay specificity and enabling detection of the variety of Neu5Gc-bearing N-glycans. By combining orthogonal dimensions of evidence, including chromatographic separation, isotopic distribution matching, and composition-confirming MS/MS, LC-MS confidently resolved Neu5Gc signals from noise, even at low abundance. In comparison, DMB-LC-FLR was limited to two orders of magnitude dynamic range, insufficient for detection of Neu5Gc in commercially available pooled human sera. These findings strongly support that DMB-LC-FLR assay specificity and sensitivity are insufficient for Neu5Gc detection in human samples due to noise overwhelming the Neu5Gc signal. By establishing a reusable benchmarking framework for future glycomic studies, we aim to use LC-MS to improve the measurement of Neu5Gc in clinical samples.

biochemistry↗

bioRxiv2023

African elephants address one another with individually specific calls

Personal names are a universal feature of human language, yet few analogs exist in other species. While dolphins and parrots address conspecifics by imitating the calls of the addressee 1,2, human names are not imitations of the sounds typically made by the names owner 3. Labeling objects or individuals without relying on imitation of the sounds made by that object or individual is key to the expressive power of language. Thus, if non-imitative name analogs were found in other species, this could have important implications for our understanding of language evolution. Here, we show that wild African elephants address one another with individually specific calls without any evidence of imitating the receivers vocalizations. A random forest model correctly predicted receiver identity from call structure better than expected by chance, regardless of whether the calls were more or less similar to the receivers calls than typical for that caller. Moreover, elephants differentially responded to playbacks of calls originally addressed to them relative to calls addressed to a different individual, indicating that they can determine from a calls structure if it was addressed to them. Our findings offer the first evidence for a non-human species individually addressing conspecifics without imitating the receiver.

animal behavior and cognition↗

bioRxiv2022

Reduced stroke outcome in old-aged female mice maintained on a dietary vitamin B12 deficiency

The global population is aging and the prevalence of age-related diseases, such as stroke, is predicted to increase. A vitamin B12 deficiency (vit. B12 def.) is common in the elderly, because of changes in metabolism. Clinical studies have reported that a vit. B12 def results in worse outcome after stroke, the mechanisms through which a vit. B12 def. changes the brain requires further investigation. This study investigated the role of vit. B12 def. on stroke outcome and mechanisms using aged female mice. Eighteen month old females were put on a control or vit. B12 def. diet for four weeks, after which an ischemic stroke was induced in the sensorimotor cortex. After damage, motor function was measured and animals were euthanized and tissues were collected for analysis. Vit. B12 def. animals had increased levels of total homocysteine in plasma and liver, choline levels were also increased in the liver. Vit. B12 def. animals had larger damage volume in brain tissue and more apoptosis. In the cecum, changes in creatinine and methylmalonic acid were observed in vit. B12 def. animals, pathway analysis showed dysfunction in B12 transport. Analysis of mitochondrial metabolomics in brain tissue showed reduced levels of metabolites involved in the TCA cycle in vit. B12 def animals. Meanwhile, pathway analysis showed significant, widespread dysfunction in phenylalanine, tyrosine, and tryptophan biosynthesis. Motor function after stroke was impaired in vit. B12 def. animals. A dietary vitamin B12 deficiency impairs motor function through increased apoptosis and changes in mitochondrial metabolism in brain tissue.

physiology↗

bioRxiv2021

N-glycolylneuraminic acid serum biomarker levels are elevated in breast cancer patients at all stages of disease.

BackgroundNormal human tissues do not express glycans terminating with the sialic acid N-glycolylneuraminic acid (Neu5Gc), yet Neu5Gc-containing glycans have been consistently found in human tumor tissues, cells and secretions and have been proposed as a cancer biomarker. We engineered a Neu5Gc-specific lectin called SubB2M, and previously reported elevated Neu5Gc biomarkers in serum from ovarian cancer patients using a Surface Plasmon Resonance (SPR)-based assay. Here we report an optimized SubB2M SPR-based assay and use this new assay to analyse sera from breast cancer patients for Neu5Gc levels. MethodsTo enhance specificity of our SPR-based assay, we included a non-sialic acid binding version of SubB, SubBA12, to control for any non-specific binding to SubB2M, which improved discrimination of cancer-free controls from early-stage ovarian cancer. We analysed 96 serum samples from breast cancer patients at all stages of disease compared to 22 cancer-free controls using our optimized SubB2M-A12-SPR assay. We also analysed a collection of serum samples collected at 6 monthly intervals from breast cancer patients at high risk for disease recurrence or spread. ResultsAnalysis of sera from breast cancer cases revealed significantly elevated levels of Neu5Gc biomarkers at all stages of breast cancer. We show that Neu5Gc serum biomarker levels can discriminate breast cancer patients from cancer-free individuals with 98.96% sensitivity and 100% specificity. Analysis of serum collected prospectively, post-diagnosis, from breast cancer patients at high risk for disease recurrence showed a trend for a decrease in Neu5Gc levels immediately following treatment for those in remission. ConclusionsNeu5Gc serum biomarkers are a promising new tool for early detection and disease monitoring for breast cancer that may complement current imaging- and biopsy-based approaches.

cancer biology↗

bioRxiv2020

The non-typeable Haemophilus influenzae major adhesin Hia is a dual function lectin that binds to human-specific respiratory tract sialic acid glycan receptors.

NTHi is a human-adapted pathogen that colonises the human respiratory tract. Strains of NTHi express multiple adhesins, however there is a unique, mutually exclusive relationship between the major adhesins Hia and HMW1/2. Approximately 25% of NTHi strains express Hia, a phase-variable autotransporter protein, and which has a critical role in colonisation of the host nasopharynx. The remaining 75% of strains express HMW1/2. Previous work has shown that the HMW1 and HMW2 proteins mediate binding to 2,3- and 2,6-linked sialic acid glycans found in the human respiratory tract. Here we show that that the high affinity binding domain of Hia, binding domain 1 (BD1) is responsible for binding to 2,6-sialyllactosamine glycans. BD1 is highly specific for glycans that incorporate the form of sialic acid expressed by humans, N-acetylneuraminic acid (Neu5Ac). We further show that Hia has lower affinity binding activity for 2,3-linked sialic acid and that this binding activity is mediated via a distinct domain. Thus, Hia with its dual binding activities functionally mimics the combined activities of the HMW1 and 2 adhesins. In addition, we show that Hia has a role in biofilm formation by strains of NTHi that express the adhesin. Knowledge of the binding affinity of a major NTHi adhesin, and putative vaccine candidate, will direct and inform development of future vaccines and therapeutic strategies for this important pathogen. ImportanceHost-adapted bacterial pathogens like NTHi have evolved specific mechanisms to colonize their restricted host niche. Relatively few of the adhesins expressed by NTHi have been characterized as regards their binding affinity at the molecular level. In this work we show that the major NTHi adhesin, Hia, preferentially binds to Neu5Ac-2,6-sialyllactosamine, the form of sialic acid expressed in humans. The receptors targeted by Hia in the human airway mirror those targeted by influenza A virus and indicates the broad importance of sialic acid glycans as receptors for airway pathogens.

microbiology↗